Find f′(x), f′′(x), and f′′′(x) for the following functions. f(x) = (x2 - 7x - 8) / (x + 1)
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Step 1: Identify the function f(x) = \frac{x^2 - 7x - 8}{x + 1}. This is a rational function, so we will use the quotient rule to find the derivatives.
Step 2: Recall the quotient rule for derivatives: if you have a function \frac{u(x)}{v(x)}, then its derivative is given by \frac{d}{dx}\left(\frac{u}{v}\right) = \frac{u'v - uv'}{v^2}. Here, u(x) = x^2 - 7x - 8 and v(x) = x + 1.
Step 3: Compute the first derivative f'(x) using the quotient rule. First, find the derivatives of the numerator and denominator: u'(x) = 2x - 7 and v'(x) = 1. Then apply the quotient rule: f'(x) = \frac{(2x - 7)(x + 1) - (x^2 - 7x - 8)(1)}{(x + 1)^2}.
Step 4: Simplify the expression for f'(x) by expanding and combining like terms in the numerator. This will give you a simplified form of the first derivative.
Step 5: To find the second derivative f''(x), differentiate f'(x) using the quotient rule again. Finally, differentiate f''(x) to find the third derivative f'''(x), ensuring to simplify at each step.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Differentiation
Differentiation is the process of finding the derivative of a function, which represents the rate of change of the function with respect to its variable. It is a fundamental concept in calculus that allows us to analyze the behavior of functions, including their slopes and rates of change. The first derivative, f′(x), gives the slope of the tangent line to the curve at any point x.
Higher-order derivatives are derivatives of derivatives. The second derivative, f′′(x), provides information about the curvature of the function, indicating whether the function is concave up or down. The third derivative, f′′′(x), can give insights into the rate of change of the curvature, which is useful in understanding the function's behavior in more detail.
The Quotient Rule is a formula used to differentiate functions that are expressed as the quotient of two other functions. If f(x) = g(x)/h(x), the derivative is given by f′(x) = (g′(x)h(x) - g(x)h′(x)) / (h(x))². This rule is essential for the given function, as it involves dividing a polynomial by another polynomial, requiring careful application of this rule to find the derivatives accurately.